COVID-19 News: Canadian Study Shows That Quercetin Not Ony Inhibits SARS-CoV-2 But It Also Prevents Syncytium Formation!

COVID-19 News: In the ongoing global struggle against the COVID-19 pandemic, a recent Canadian study has unveiled promising revelations regarding the potential of quercetin, a plant flavonol, in inhibiting SARS-CoV-2 infection and preventing syncytium formation. This research covered in this COVID-19 News report, not only sheds light on quercetin's inhibitory effects but also delves into the intricate molecular mechanisms underlying its impact on the virus, offering a potential new avenue in the fight against COVID-19.


Quercetin Not Ony Inhibits SARS-CoV-2 But It Also Prevents Syncytium Formation
 
Thailand Medical News had covered previous studies on the merits of using Quercetin in COVID-19 and even in Long COVID.
 
https://www.thailandmedical.news/news/covid-19-supplements-numerous-studies-show-that-the-phytochemical-quercetin-not-only-inhibits-sars-cov-2-but-helps-in-other-aspects-of-covid-19
 
https://www.thailandmedical.news/news/breaking-supplements-for-covid-19-quercetin-emerging-as-an-adjuvant-for-covid-19-treatments
 
https://www.thailandmedical.news/news/covid-19-news-mexican-scientists-recommend-quercetin-for-oxidative-stress-issues-in-long-covid
 
https://www.thailandmedical.news/news/quercetin-emerging-as-one-of-the-must-take-covid-19-supplements-especially-when-considering-the-omicron-variant-and-long-covid-19-issues
 
https://www.thailandmedical.news/news/covid-19-news-insights-into-the-mechanism-behind-covid-19-induced-acute-kidney-injury-and-the-potential-therapeutic-role-of-quercetin
 
https://www.thailandmedical.news/news/flavonoids-epigallocatechin,-baicalin,-hesperetin,-luteolin-and-quercetin-helps-prevent-covid-19-induced-gastrointestinal-inflammation-and-diarrhea
 
Background - SARS-CoV-2's Relentless Att ack and the Quest for Solutions
SARS-CoV-2, the virus responsible for COVID-19, predominantly targets respiratory epithelial cells, initiating a cascade of symptoms and potential complications that have led to the urgent quest for effective therapeutic strategies. The severity of the disease has prompted intensive research into potential treatments to mitigate infection, viral replication, and the associated inflammatory responses. This study investigates the potential of quercetin, a naturally occurring compound with notable antioxidant and anti-inflammatory properties, to be a game-changer in the fight against COVID-19.
 
Understanding the SARS-CoV-2 Life Cycle
The entry of SARS-CoV-2 into human cells involves a complex dance of molecular interactions. The viral Spike (S) protein binds to human angiotensin-converting enzyme 2 (ACE2), initiating a series of proteolytic cleavages by enzymes like furin. This orchestrated molecular ballet facilitates viral entry and replication. Inhibition of these processes presents a promising avenue for therapeutic intervention. Existing antiviral strategies include vaccines, decoy ACE2, and various enzyme inhibitors targeting viral proteins.
 
Quercetin Emerges as a Multifaceted Player
Quercetin, a flavonol found in various plants, has garnered attention due to its potential to interact with multiple proteins involved in the SARS-CoV-2 life cycle. Molecular docking studies revealed strong affinity between quercetin and viral proteins, including the S protein, 3CLpro, and RdRp, as well as cellular ACE2 and TMPRSS2. Beyond its potential interference with viral proteins, quercetin's antioxidant and anti-inflammatory properties make it an intriguing candidate for COVID-19 therapy.
 
Experimental Approach - Unraveling Quercetin's Impact on SARS-CoV-2
The Canadian study employed an ex vivo approach, infecting Vero E6 and Caco-2 cells with SARS-CoV-2 and exposing them to varying concentrations of quercetin. The results demonstrated a concentration-dependent inhibition of viral replication, with half inhibitory concentrations (IC50) of 166.6 µM and 145.2 µM for Vero E6 and Caco-2 cells, respectively. These findings suggest that quercetin negatively impacts virus replication at concentrations achievable in a laboratory setting.
 
Syncytium Formation - A Crucial Step in Viral Propagation
The study extended its investigation to syncytium formation, a mechanism that promotes viral propagation. Syncytia are formed when infected cells fuse, creating a larger, multi-nucleated cell. To mimic this process, the researchers used human embryonic kidney HEK293 cells co-expressing SARS-CoV-2 S protein and ACE2. Quercetin demonstrated an inhibitory effect on syncytialization with an IC50 of 156.7 µM, suggesting its potential to impede this cytopathic effect.
 
Molecular Insights - Quercetin's Impact on S Protein and ACE2
The study delved into the molecular mechanisms underlying quercetin's inhibitory effects. Expression of the S protein and ACE2 was associated with decreased expression, increased proteolytic processing of the S protein, and diminished production of the fusogenic S2’ fragment of S. Furin, a key protease in this process, was inhibited by quercetin in vitro with an IC50 of 116 µM. This suggests that quercetin's reduction of furin-mediated production of the S2’ fusogenic fragment might contribute to the observed reduction in syncytium formation.
 
Quercetin and Inhibition of Syncytium Formation
Syncytium formation is a critical step in the viral life cycle, facilitating the spread of infection. The study utilized a HEK293 cell-based assay to demonstrate that quercetin, at concentrations above 100 µM, hindered syncytium formation. Confocal microscopy revealed a reduction in the clusters of fused cells, indicating the flavonol's potential to impede this cytopathic effect. The molecular dance between the S protein and ACE2, orchestrated by quercetin, showcases the complexity of cellular interactions in the battle against SARS-CoV-2.
 
Exploring Clinical Implications - Beyond the Lab Bench
While the concentrations of quercetin used in the study are higher than typically found in blood after oral administration, previous studies suggest the potential accumulation of quercetin in the lungs, a primary target organ for SARS-CoV-2. The study highlights the need for further experimental evaluation, including in vivo studies on appropriate animal models and eventually clinical trials in human patients, to validate quercetin's efficacy as a potential anti-COVID-19 drug. These future investigations will provide valuable insights into the practical applications of quercetin in real-world scenarios.
 
Conclusion: A New Ray of Hope in the Battle Against COVID-19
The Canadian study not only provides compelling evidence for the inhibitory effects of quercetin on SARS-CoV-2 infection and syncytium formation but also delves into the intricate molecular mechanisms governing these interactions. As the world continues its fight against the COVID-19 pandemic, the quest for effective therapeutic options takes a significant step forward with the revelation of quercetin's potential impact on SARS-CoV-2. This multifaceted plant flavonol has emerged as a potential game-changer, offering hope in the relentless pursuit of solutions. Further research, clinical trials, and real-world applications are crucial to unlocking the full therapeutic potential of quercetin in the battle against COVID-19.
 
The study findings were published in the peer reviewed journal: Virology Journal.
https://virologyj.biomedcentral.com/articles/10.1186/s12985-024-02299-w
 
Thailand Medical News would like to warn readers that when buying Quercetin supplements, be very careful as due to lax in labelling laws pertaining to supplements and the fact there are many forms of Quercetin, many supplement companies that merely using forms of Quercetin that literally have no bioactive benefits! For example, the study itself found that Quercetin-3-glucoside also known as isoquercetin or isoquercitrin - which is less hydrophobic than quercetin, and thus less membrane-intercalating, failed to inhibit syncytium formation. Many supplement companies use this cheaper form of isoquercetin in their supplements and label it as Quercetin! Also, never buy any supplements made by companies owned by ethnic Indians especially those made in many South East Asian countries and now even in many South American countries.Also never purchase Quercetin in liquid forms as they tend to lose their bioactiveness faster due to oxidation.
 
For the latest COVID-19 News, keep on logging to Thailand Medical News.
 
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